While I do not want/need body armor, I was still curious of the price. So looked up that level 3 Spartan Armor plate and it is anywhere from $385 to $685, depending on the materials. Which made me look up how much Kevlar was needed to stop a 5.56, had he used it. So here is a video from a soft armor (loose layers sewn together) manufacturer testing just that. They got up to 45 layers of Kevlar before it stopped the round.
Still, you can buy Kevlar for $50 a yard (50'" wide), which means you could probably make a riffle resistant, yet rather thick, chest "plate" for less than $300. No clue if pressure molding it with resin would increase or decrease layers needed or thickness (if it needed more layers).
Ive always thought the loss of the old tech was like the Boogey Man story or an episode of the Twilight Zone or something. Vehicles, appliances, and basically the electronics industry at large has replaced so many basic functions with a processor because it actually ends up being cheaper to have one central processor do all the functions instead. We're old enough to have seen all this old tech in action, and be familiar with it. But lets say a major war happens that wipes out a large percentage of the worlds population and with it, the ability and the know how to create processors or something else thats integral? Look how quickly books have been phased out over the last 15 years. Imagine 30 more years. As if all that many people would have the basic principles of how to create a processor in book format, somewhere safe from time and damage, anyways.
I guess we could hope that we have a black historian / librarian hologram that'll teach us shit while his futuristic ancestors try to capture us.